1. Field of the Invention
The present invention relates to a method for controlling browning reactions in foods using noble gases, or mixtures of noble gases or gaseous mixtures containing noble gases.
2. Description of the Background
The reaction of reducing sugars with amino acids is formally known as the Maillard reaction and is involved in the nonenzymatic browning of foods during cooking, processing and storage. This reaction is also generally known as the "browning" reaction. During cooking or other food processing, this reaction is often desired in order to impart favorable coloration to the final product, such as in the baking of bread or the caramelization of confections. In certain other food processing operations, which may or may not involve cooling or heating, the reaction is considered undesirable, such as in the storage of white sugar. Additionally, milk products are also susceptible to browning discoloration due to the Maillard reaction.
At present, methods of controlling browning reactions are limited to the control of process parameters, such as the amount of moisture or oxygen present in the atmosphere of the general process.
For example, in processing milk products, control of the Maillard reaction may be effected to some extent by maintaining control over reduction and oxidation potentials in the process media, by ensuring that unwanted amines or sugars are not added, by preventing unwanted reactions such as acidification of milk, by preventing contact with excess CO.sub.2, and by controlling heating carefully. Typical process improvements are disclosed in WO 8600503, DE 3425088, AU 8546026, EP 189442 and DE 3448380, in which inert or non-reactive gases, either nitrogen or a noble gas, are used to control pressure in the system so as to provide a means whereby lower temperatures may be used or boiling may be prevented or aromas may be preserved.
However, the conventional methods of attenuating the Maillard reaction are inadequate as they are incapable of effecting a direct means of control. Furthermore, no means presently exists whereby the Maillard reaction can be both accelerated and retarded as needed.
Moreover, it would be extremely desirable if a means were available for directly controlling the Maillard reaction by using a particular atmospheric composition. At present, it is considered that gases generally have no effect on the Maillard reaction. Recently, Waller, G. R. and M. S. Fezther, 1983, ACS Symposium Series 215, The Maillard Reaction in Foods and Nutrition, American Chemical Society, Washington, D.C., USA, disclosed that no influence upon the course or rate of the Maillard reaction could be attributed to any atmospheric composition, except where a reactive gas, such as carbon dioxide, might react with a component of the reaction.
However, despite conventional wisdom, a need exists for a means by which browning reactions may be directly controlled as a function of atmospheric composition.